> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tokenlab.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Cancel Task

> Cancel a queued async task when the provider and model support cancellation

## Overview

Use `DELETE /v1/tasks/{id}` to cancel an asynchronous task that has not started running yet. Use the same task ID from the create response or the returned `poll_url`.

## Supported Tasks

Cancellation is currently supported for queued Seedance video tasks using `seedance-1.5-pro`, `seedance-2.0`, or `seedance-2.0-fast` when the provider selected for that task supports cancellation. Tasks that are already `processing`/running cannot be cancelled. Completed, failed, expired, or unsupported tasks remain queryable for status and billing reconciliation.

## Path Parameters

<ParamField path="id" type="string" required>
  The async task ID returned by the create request or embedded in `poll_url`.
</ParamField>

## Response

<ResponseField name="id" type="string">
  Canonical async task identifier.
</ResponseField>

<ResponseField name="task_id" type="string">
  Async task identifier alias.
</ResponseField>

<ResponseField name="poll_url" type="string">
  Preferred polling URL for the task. It remains valid after cancellation.
</ResponseField>

<ResponseField name="status" type="string">
  Task status. A successfully cancelled task is returned as `failed` with `cancelled: true` for compatibility with existing status values.
</ResponseField>

<ResponseField name="cancelled" type="boolean">
  `true` when the task was cancelled before execution.
</ResponseField>

<ResponseField name="cancellation_status" type="string">
  Cancellation marker. The value is `cancelled` when cancellation succeeds.
</ResponseField>

<ResponseField name="error" type="string">
  Cancellation reason or task failure message.
</ResponseField>

## Error Behavior

`400 unsupported_task_cancel` means the task type, provider, or model does not support cancellation. `409 task_not_cancellable` means the task is already processing, terminal, or otherwise no longer cancellable. `403` means the API key cannot access the task.

## Example

<RequestExample>
  ```bash cURL theme={null}
  curl -X DELETE "https://api.tokenlab.sh/v1/tasks/ldtask_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" \
    -H "Authorization: Bearer sk-your-api-key"
  ```
</RequestExample>

```json Response theme={null}
{
  "id": "ldtask_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "task_id": "ldtask_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "poll_url": "/v1/tasks/ldtask_aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
  "status": "failed",
  "cancelled": true,
  "cancellation_status": "cancelled",
  "error": "Task cancelled before execution"
}
```